1. Field of the Invention
The present invention pertains to a method and an apparatus to fabricate a liquid crystal display panel, and more particularly, to a method and an apparatus to fabricate a liquid crystal display panel capable of selectively forming a spacer at a desired area.
2. Description of the Related Art
A liquid crystal display device typically controls the light transmittance of liquid crystal by using an electric field to display a picture. To this end, the liquid crystal display device includes a liquid crystal display panel in which liquid crystal cells are arranged in a matrix, and a drive circuit for driving the liquid crystal display panel.
The liquid crystal display panel includes a thin film transistor array substrate and a color filter array substrate, which face each other.
The color filter array substrate includes gate lines and data lines, a thin film transistor of a switching device formed at each crossing of the gate lines and the data lines, a pixel electrode formed at each liquid crystal cell and connected to the thin film transistor, and an alignment film coated on top of them.
The color filter array substrate includes color filters formed at each liquid crystal cell, a black matrix that partitions the color filters and reflects external light, a common electrode to commonly apply a reference voltage to liquid crystal cells, and an alignment film coated on top of them.
Spacers between the color filter array substrate and the thin film transistor array substrate sustain a defined cell gap between the substrates.
FIG. 1 shows a diagram representing a related art spacer spray device to form spacers.
Referring to FIG. 1, the related art spacer spray device includes a feed box 12 containing ball spacers 10. A chamber 4 with a nozzle 8 for sprays the ball spacers 10 in the feed box 12 on a substrate 2 through a pipe 14.
The feed box 12 stores the ball spacers 10 destined to be sprayed on the substrate 2. Nitrogen gas N2 injected from the exterior supplies the ball spacers 10 stored in the feed box 12 to the pipe 14.
The chamber 4 contains the substrate 2 mounted on a stage 6, and a nozzle 8 for spraying the ball spacers 10 on the substrate 2. The nozzle 8 located on the upper part of the substrate 2 sprays the ball spacers 10 on the substrate 2 while moving at a designated speed. The substrate 2 is either the thin film transistor array substrate having thin film transistors and pixel electrodes formed thereon or the color filter array substrate having color filters formed thereon.
The operation of the related art spacer spray device is described below.
First, nitrogen gas is supplied to the feed box 12 through a supply line (not shown), and the ball spacers 10 stored in the feed box 12 are supplied to the pipe 14 by the nitrogen gas. At this moment, the ball spacers 10 collide with the inner wall of the pipe 14 while moving along the pipe 14. The ball spacers 10 are thus charged with positive (+) charges by the triboelectric effect. The positively charged ball spacers are sprayed uniformly on the substrate 2 through the nozzle 8, as shown in FIG. 2.
However, if an undesired electric field associates with the metal patterns on the substrate 2 in the chamber 4, then the positive (+) charged ball spacers 10 concentrate on a pattern to which negative (−) voltage on the substrate 2 is applied, as shown in FIG. 3. In this case, if a display area has an area “A” concentrated by the ball spacers 10, the ball spacers 10 appear as stains in the display area.
Further, the ball spacers 10 tend to easily move when impacted from the exterior, and thus an alignment film adjacent to the ball spacers 10 in the display area is damaged. Accordingly, the alignment of the liquid crystal material becomes uneven to cause its brightness to deteriorate. As a result, new spacer technologies are needed to produce high quality displays.